This invention relates to a process for the extraction and recovery of polyhydroxyalkanoate (PHA) from biomass.
There has been considerable interest in recent years in the use of biodegradable polymers to address concerns over plastic waste accumulation. The potential worldwide market for biodegradable polymers is enormous. Some of the markets and applications most amenable to the use of such biopolymers involve those having single, short use applications, including packaging, personal hygiene, garbage bags, and others. These applications, although poorly suited for recycling, are ideally suited for biodegradation through composting.
PHA biopolymers are thermoplastic polyesters produced by numerous microorganisms in response to nutrient limitation. The commercial potential for PHA spans many industries, and is derived primarily from certain advantageous properties which distinguish PHA polymers from petrochemical-derived polymers, namely excellent biodegradability and natural renewability. The success of PHA as a viable alternative to petrochemical-derived polymers, however, will depend upon the design and implementation of efficient and selective means of PHA production and recovery.
An improved understanding of the biology of PHA biosynthetic pathways has allowed for the use of microbial organisms, both natural and recombinant, and more recently plant cells, to produce significant quantities of PHA. Although such approaches have identified promising routes to PHA production, there remain obstacles to efficient and cost-effective PHA recovery from source materials at a useful level of quality and purity. Much of the effort directed to identifying methods for recovery of PHA have focused on recovery from bacterial sources using halogenated hydrocarbon solvents. The environmental implications and human toxicities associated with halogenated compounds, however, have created a need for separation processes which utilize PHA solvents with more benign properties.